Relay



Aug. 11, 1925. 1,549,734

P. M GAHAN RELAY Filed April '7, 1,920

WITNESSES: INVENTOR Y B I/ I a ATTORNEY Patented Aug. 11, 1925.

UNITED STATES PATENT OFFICE.'

PAUL MACGAHAN, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSEELECTRIC 8: MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

RELAY.

Application filed April 7,

TouZZ whom it may concern:

Be it known that I, PAUL MAGGAHAN, a citizen of the United States, and aresident of Pittsburgh, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in Relays, ofwhich the following is a specification.

My invention relates to electrical protective "devices and particularlyto relay mechanisms that are employed for tripping circuit interruptersor for operating other devices, upon the occurrence of predeterminedconditions.

The object of my invention is to provide a simple and economical relaymechanism, of the character indicated, that may be operated by thecurrent derived from the circuit in connection with which theinterrupter or other device is employed, thereby obviating the necessityofv employing a separate source of power to operate the same and alsoobviating the use of contact members which are subjected to injuriousarcing and to the possibility of welding or sticking together.

Considerable difficulty has heretofore been experienced with relaymechanisms of circuit interrupters, or similar devices, that areemployed in connection with alternatingcurrent circuits when it has beenattempted to derive energy from the said circuits for tripping 'oroperating the interrupt-ers. This difficulty has been caused by reasonof the fact that the energy for operating the relay mechanism and fortripping the circuit interrupter has usually been derived from the maincircuit by means of a series transformer, the secondary circuit of whichincluded the operating coil of the relay, the tripping coil of thecircuit interrupter, and relay contact members which normallysh-ort-circuited the latter 'coil but were separated to permititsenergization upon the occurrence-of an overload or other predeterminedcircuit condition. -There is usually a sufficient amount of current inthe second: ary circuit to cause arcing at the relay contact members,and, at times, it may be suflicient to cause them to ,weldtogether, thedifiiculty being most serious when there is a slow separation of thecontact members 1920. Serial No. $7 1,920.

by reason of the employment of a dash pot or other retarding device forintroducing a time interval between the occurrence of the overload andthe opening of the circuit interrupter. Furthermore, arcing between thecontact members may so burn and injure them as to prevent them frommaking good electrical contact when brought into engagement.

I provide a tripping device that is supplied with energy from the maincircuit but does not require the interruption of a circuit, therebyovercoming the hereinbefore-mentioned difficulties.

The single figure of the accompanying drawing is a diagrammatic view ofa part of an electrical system embodying my invention.

A typicalsystem, in connection with which my invention maybe employed,comprises an alternating-current circuit 1 that is adapted to beinterrupted by means of a circuit interrupter 2 and in series relationwith one conductor of which is connected a current transformer 3. Thecircuit of the secondary winding 4 of the current transformer includes'a winding -5 of a relay 6 and a winding 7 of a relay 8. The relay 6 maybe of any suitable construction, such as either an instantaneous,inverse or definite time-limit relay, having two contact members 9 and'10, engagement of which may be effected upon the occurrence of certainpredetermined conditions in the circuit 1. The relay 8 comprises amagnctizable core member 11 of E-sha-pe, that has the main winding 7disposed on the middle lateral portion 12 thereof, .and that has twoauxiliary windings 13 and M disposed on the end lateral portions 15 andi 16, respectively, of the core member 1]. The relay 8 further comprisesa movable armature member 17 so pivoted at a point 18 adjacent the endof the middle lateral portion 12 that it may complete the magneticcircuits comprising the middle lateral portion 12 and either of the endportions 15 and 16. An adjustable stop 19 is disposed atthe end of thearmature member adjacent the end portion 16 and serves to prevent actualengagement between the armature member 17 and the lateral end portion15. The terminals of the winding 13 that is disposed on the lateral endportion 15 are respectively connected to the contact members 9 and 10 ofthe relay 6. The winding 14: that is disposed on the lateral end portion16 is connected across a winding 20 that energizes the tripping magnet21 which actuates the circuit interrupter-2.

When current traverses the circuit 1, the winding 7 of the relay 8 isenergized by means of the current transformer 3 and serves to energizethe core member. 11. Since the winding 14 of the relay 8 is alwaysshort-circuited by the tripping magnet wi nding 20, the armature member17 tends to complete the magnetic circuit comprising the middle lateralportion 12 and the end lateral portion 15. The :uljustable stop member19 serves to preclude actual engagement between the movable armaturemember 17 and the lateral portion 15 of the core member 11. The armaturemember 17 may, however, efiect actual engagement with the lateral endportion 16. When the relay 8 is energized in accordance with a normalvalue of current that traverses the circuit 1, the armature member 17will be attracted toward the lateral end portion 15 because thereluctance of the magnetic path that includes the portion 15 is lessthan the relueta ance of the magnetic path that includes the portion 16.When the current that traverses the circuit 1 attains a predeterminedvalueand is maintained at, or above, that value for an interval of timecorresponding to the time-setting of the relay 6, the relay 6 becomes soenergized as to effect engage: ment between its contact members 9 and10, thus short-circuiting the winding 13 disposed on the lateral endportion15. The winding 13, being short-circuited, tends to do sosuddenly increase the reluctance of the magnetic path that includes thelateral end portion 15 as to permit a greater degree of magnetization inthe magnetic circuit that includes the lateral end portion 16.

v cuited winding The armature member 17 is thereupon attracted to theend portion 16 and so com-,

pletes the magnetic circuit including said end portion 16 as to permitthe winding 14 to be sufiiciently energized to actuate the trippingmagnet 21 of the interrupter 2.

en the circuit interrupter 2 is actuated, the relay 6 becomes sode-energized as to effect disengagment beween its contact members 9 and10 and to open the circuit of the wmding 13. Upon the reclosing of thecircuit interrupter 2 and the subsequent re-energization of the relay 8,the armature member 17 is immediately attracted to the end lateralortion 15 because of the greater reluctance t at is effected by theclosed-cir- 14 in the magnetic circuit that includes the end portion 16.The

mature member 17 thus automatically biases itself in the desiredposition.

While I have shown a preferred form of relay embodying my invention, Ido not limit it to the structure as shown, as various modifications maybe made therein without departing from the spirit and scope of theinvention as set forth in the appended claims.

I claim as my invention:

1. A relay device comprising a magnetizable core member having one mainwinding and a plurality of secondary windings disposed thereon that areindependent of the main winding and of each other, and means for varyingthe inductive relation between the main winding and the secondarywindings.

2. A relay device coi'nprising a magnetizable core member having onemain winding and a plurality of secondary windings disposed thereon thatare independent of the main winding and of each other, and meansresponsive to the electrical condition of the main winding forcontrolling the inductive relation between predetermined windings.

3. In an electric circuit, the combination with a core member having twomagnetic paths including a common portion and a netic path and isadapted tobe inductively 4 energized by the first winding when thearmature member is actuated to the second magnetic path.

' 4. In an electromagnet, the combination with a core member and amovable armature member, of a plurality of close-circuited windingsinductively related to each other and means comprising a normally opencircuited winding for changing the inductive relations between the otherwindings.

5. In an electric circuit, the combination with a circuit interrupterand a trip coil therefor, of means for controlling the energization ofthe trip coil comprising an electromagnet having a core member embodyingtwo magnetic paths, a movable armature member for completing themagnetic circuit of either path and a main winding energized from thecircuit for energizing the magnet, an auxiliary winding normallyopen-circuited and adapted to repulse the armature member from thecorresponding magnetic circuit when short circuited, and a secondauxiliary winding connected in closed-circuit relation to the trip coilof the interrupter and inductively energized from the main winding uponthe completion of its magnetic circuit by the armature member.

6. In an electric circuit, an electromagnet comprising a main windingenergized from the circuit and two auxiliary windings one of which isenergized under certain conditions in the circuit and the other of whichis thereupon inductively energized from the main winding.

7. In an electric circuit, the combination with a circuit-interrupterand a tripping magnet therefor, of an elect-roma'gnet having a mainwinding energized from the circuit, an auxiliary winding normallyopencircuited and inductively related to the main winding, and a secondauxiliary winding inductively related to the main winding and energizedthereby to energize the tripping magnet when the first auxiliary windingis short-circuited upon the occurrence of predetermined conditions inthe circuit.

8. In an electric circuit, the combination with a circuit-interrupterand a tripping magnet therefor, of a relay comprising a magnetizablecore member of E-shape having a winding disposed on each lateralportion, and a movable magnetizable armature member pivoted adjacent themiddle portion and adapted to complete the magnetic circuiton eitherside of said portion to change the relative inductive relations betweenthe winding disposed on the middle portion and each of the windingsdisposed on the end portions of the core member, one of thelastmentioned windings being connected to the tripping magnet toenergize the same under predetermined conditions.

9. In an electric circuit, the combination with a circuit-interrupterand a tripping magnet therefor, of a relay comprising a core member ofE-shape having a winding disposed on the middle lateral portion.energized from the circuit, a movable; armature member pivoted adjacentsaid portion, a normally open-circuited winding on one end portionadapted to be short-circuited upon the occurrence of predeterminedconditions in the circuit, and a winding disposed on the other endportion and adapted to energize the tripping magnet of the interrupterwhen the short-circuiting of the winding on the first end portion shiftsthe magnetic flux from that end portion to the other end portion.

10. In an electric circuit, the combination with a circuit-interrupterand a tripping magnet therefor, of a relay-comprising a core member ofE-shape, a movable armature member so pivoted adjacent the middleportion of the core member as to complete the magnetic circuit on eitherside thereof and normally biased toward one end portion of the coremember, a normally open-circuited winding disposed on said end portionadapted be so short-circulted upon the occurrence of predeterminedconditions in the circuit as to repulse the armature member from saidend portion to complete the magnetic circuit of the other end portion, awinding on said other end portion adapted to be so energized upon theactuation of the armature member thereto as to energize the trippingmagnets of the circuit-interrupter.

11. Inan electric circuit, the combination with a circuit-interrupterand a tripping magnet therefor, of a relay comprising a magnetizablecore member having a winding energized from the circuit to be pro tecteddisposed thereon, a time-element relay similarly energized from thecircuit, a normally open-circuite-d winding inductively related to thecircuit-energized winding and adapt-ed to be short-circuited by thetimeelement relay, and a second winding inductively related to theshort-circuiting of the normally open-circuited Winding to actuate thetripping magnet of the circuit interrupter.

12. An electromagnet comprising a mag netizable core member having twomagnetic circuits of'variable reluctance with a portion of each circuitcommon to both and a pivoted armature member to complete either magneticcircuit, a winding for energizing the core member, an auxiliary windingnormally open-circuited and adapted to be so short-circuited upon theoccurrence of predetermined conditions as to increase the reluctanceofthe corresponding magnetic circuit and to simultaneously decrease thereluctance of the second magnetic circuit, and

a second auxiliary winding inductively energized upon the decrease inreluctance of the second magnetic circuit.

13. An electromagnet comprising a magnetizable core member having amovable armature member and two magnetic paths for the flux thattraverses the armature, each of which includes a variable air gap, awinding for energizing the core member and two independent secondarywindings, one of which is'associated with each of the two magneticpaths.

14. An electromagnet comprising a mag netizable core member having amovable armature member and two magnetic paths for the flux thattraverses the armature, each of which includes a variable air gap, amain win-ding for energizing the coremember, two secondary windingsindependent of the main winding and severally associated with each ofthe magnetic paths and means for varying the inductive relation betweenthe main windings and the secondary windin s.

l5. An electromagnet comprising a magnetizable core member having onemain winding and two independent secondary windings disposed thereon,and means for varying the inductive relations between the main windingand each of the secondary for varying the inductive relation betweenwindings. two of the windings.

16. Arelay device comprising a magnetim In ijestimony whereof, havehereunto 10 able core member having one main Winding su scrlbed my namethis 26th day of and a plurality of secondary windings dis- March, 1920-posed thereon that are independent of the main winding and of eachother, and means PAUL MAGGAHAN.

